It is well known that people have needed the ability to accurately tell time. As human mobility has increased so has the need to have a portable source that can keep time. Originally, the pocket watch was invented that mainly consisted of watch gears surrounded in a metal casing. The metal casing protected the glass face of the pocket watch from accidental scratching or damage. The pocket watch has been slowly replaced by wristwatches, which provided an easier mobility and easy since they were not carried in the users pocket. As a consequence of the new ease of mobility created by the wristwatch, the damage to the class covering the watch hands and gears has become more prevalent. Therefore, it has become advantageous to for wristwatches to be designed for scratch-resistance.
One of the main methods to achieve scratch-resistance is by using scratch resistant glass or crystal to cover the watch face. Scratch-resistant substances have had many applications and their use in watches has great advantages since the watch lens is not significantly more difficult to be damaged. However, the additional cost of a scratch-resistant glass watch makes the use of such glass less desirable, in addition to that the glass is scratch-resistant and not scratch proof. The use of plastic as a watch cover has been used as well. Whereas, this change in material addresses the cost factor, it is rarely as clear as glass or crystal and does not provide the aesthetic appeal many watch owners' desire. In addition, plastic is usually easy to scratch, but more difficult to crack than its glass counterpart.
Another method of scratch resistance has been by using a guard that surrounds the watch face. This guard prevents the user from scratching the glass face of the watch when laying it face down. These guards, however, limit the viewing angle of the watch face and make time reading somewhat difficult.